A starter is generally used to start an engine in an automobile. The power of the starter is provided by a battery, e.g. a lead-acid storage battery. When the engine is working, a generator of the automobile supplies power to the electric devices in the automobile via the lead-acid storage battery, and the battery plays a role for voltage stabilization. When the engine stops, the lead-acid storage battery supplies power directly to the electric devices in the automobile. When the engine starts, it is desired to provide a current of several hundred amperes by the lead-acid storage battery to ensure successful starting of the automobile. However, the instantaneous high current discharging is extremely harmful to both the lifetime and performance of the lead-acid storage battery. Moreover, the lead acid storage battery has a low power density and insufficient discharging ability, and is not environmentally friendly. In contrast, a super capacitor has fast charging and discharging capability and has a lifetime of 500 thousands charge-discharge cycles. If the advantages of the lead-acid battery and the super capacitor can be combined, the technical requirements can be satisfied with both economical and environmental social benefits.
Chinese patent publication CN201927685U discloses a new energy source type of battery, said battery having a housing, wherein said housing having both a battery housing and a capacitor housing. A lead-acid battery pack connected in series is disposed within the battery housing. Separator plates are disposed within the lead-acid battery pack, and lead-acid battery poles are connected to the separator plates. A super capacitor is disposed within the capacitor housing, and capacitor poles are connected to the super capacitor, which are connected with the lead-acid battery poles are connected via metal wires. The patent application mainly solves certain technical problems existed in prior art, i.e., the lead-acid battery is low in power density and has insufficient instantaneous discharging capability, the capacity of the batteries used is higher than actual requirement to ensure the startup capability, the storage battery has a short lifetime due to the high current discharging, and is expensive, heavy and bulky. However, when the engine starts, it is still powered by the lead-acid storage battery and the super capacitor together, such that the instantaneous current flowing through the lead-acid storage battery will not be low and the lead-acid storage battery is not fully protected. Said parallel connection of the lead-acid storage battery and the super capacitor alone can not fully exploit the advantage of the super capacitors.